GAMS

GAMSShell Solver

`GAMSShell.available`([exception_flag])	True if the solver is available.
`GAMSShell.executable`()	Returns the executable used by this solver.
`GAMSShell.solve`(args, *kwds)	Solve a model via the GAMS executable.
`GAMSShell.version`()	Returns a 4-tuple describing the solver executable version.
`GAMSShell.warm_start_capable`()	True is the solver can accept a warm-start solution.

class pyomo.solvers.plugins.solvers.GAMS.GAMSShell(**kwds)[source]

A generic shell interface to GAMS solvers.

available(exception_flag=True)[source]: True if the solver is available.

executable()[source]: Returns the executable used by this solver.

solve(*args, **kwds)[source]

Solve a model via the GAMS executable.

Keyword Arguments:

tee=False (bool) – Output GAMS log to stdout.
logfile=None (str) – Filename to output GAMS log to a file.
load_solutions=True (bool) – Load solution into model. If False, the results object will contain the solution data.
keepfiles=False (bool) – Keep temporary files.
tmpdir=None (str) – Specify directory path for storing temporary files. A directory will be created if one of this name doesn’t exist. By default uses the system default temporary path.
report_timing=False (bool) – Print timing reports for presolve, solver, postsolve, etc.
io_options (dict) – Options that get passed to the writer. See writer in pyomo.repn.plugins.gams_writer for details. Updated with any other keywords passed to solve method. Note: put_results is not available for modification on GAMSShell solver.

GAMSDirect Solver

`GAMSDirect.available`([exception_flag])	True if the solver is available.
`GAMSDirect.solve`(args, *kwds)	Solve a model via the GAMS Python API.
`GAMSDirect.version`()	Returns a 4-tuple describing the solver executable version.
`GAMSDirect.warm_start_capable`()	True is the solver can accept a warm-start solution.

class pyomo.solvers.plugins.solvers.GAMS.GAMSDirect(**kwds)[source]

A generic python interface to GAMS solvers.

Visit Python API page on gams.com for installation help.

available(exception_flag=True)[source]: True if the solver is available.

solve(*args, **kwds)[source]

Solve a model via the GAMS Python API.

Keyword Arguments:

tee=False (bool) – Output GAMS log to stdout.
logfile=None (str) – Filename to output GAMS log to a file.
load_solutions=True (bool) – Load solution into model. If False, the results object will contain the solution data.
keepfiles=False (bool) – Keep temporary files. Equivalent of DebugLevel.KeepFiles. Summary of temp files can be found in _gams_py_gjo0.pf
tmpdir=None (str) – Specify directory path for storing temporary files. A directory will be created if one of this name doesn’t exist. By default uses the system default temporary path.
report_timing=False (bool) – Print timing reports for presolve, solver, postsolve, etc.
io_options (dict) – Options that get passed to the writer. See writer in pyomo.repn.plugins.gams_writer for details. Updated with any other keywords passed to solve method.

GAMS Writer

This class is most commonly accessed and called upon via model.write(“filename.gms”, …), but is also utilized by the GAMS solver interfaces.

class pyomo.repn.plugins.gams_writer.ProblemWriter_gams[source]

__call__(model, output_filename, solver_capability, io_options)[source]

Write a model in the GAMS modeling language format.

Keyword Arguments:

output_filename (str) – Name of file to write GAMS model to. Optionally pass a file-like stream and the model will be written to that instead.
io_options (dict) –
- warmstart=True
  Warmstart by initializing model’s variables to their values.
- symbolic_solver_labels=False
  Use full Pyomo component names rather than shortened symbols (slower, but useful for debugging).
- labeler=None
  Custom labeler. Incompatible with symbolic_solver_labels.
- solver=None
  If None, GAMS will use default solver for model type.
- mtype=None
  Model type. If None, will chose from lp, nlp, mip, and minlp.
- add_options=None
  List of additional lines to write directly into model file before the solve statement. For model attributes, <model name> is GAMS_MODEL.
- skip_trivial_constraints=False
  Skip writing constraints whose body section is fixed.
- output_fixed_variables=False
  If True, output fixed variables as variables; otherwise, output numeric value.
- file_determinism=1
  
  How much effort do we want to put into ensuring the
  
  GAMS file is written deterministically for a Pyomo model:
  
  0 : None
  
  1 : sort keys of indexed components (default)
  
  2 : sort keys AND sort names (over declaration order)
- put_results=None
  Filename for optionally writing solution values and marginals. If put_results_format is ‘gdx’, then GAMS will write solution values and marginals to GAMS_MODEL_p.gdx and solver statuses to {put_results}_s.gdx. If put_results_format is ‘dat’, then solution values and marginals are written to (put_results).dat, and solver statuses to (put_results + ‘stat’).dat.
- put_results_format=’gdx’
  Format used for put_results, one of ‘gdx’, ‘dat’.